Carbon Iso-Dielectric Separation (CIDS) on Centrifugal Microfluidic Platforms

Abstract

Centrifugal microfluidic platforms employ pseudo forces controlled by a spindle motor to automate bioanalytical assays on a single fluidic disc with no need for several syringe pumps [1]. Recently, we employed a portable cutter-plotter to fabricate microfluidic discs with active valves at point of need [2]. To address a healthcare issue of global interest, we developed a microfluidic disc to automate a sTREM-1 immunoassay for the detection of sepsis at late stages of the disease. To enable sepsis detection and monitoring at early stages, recently a gold iso-dielectric separation (GIDS) chip is develop that separates activated and non-activated leukocytes from blood serum [3]. However, the GIDS chip requires several syringe pumps and an off-chip manual step for sample preparation i.e., blood serum separation. As an alternative to GIDS, in this study we have developed 3D carbon IDS (CIDS) chips to reduce the cost of device fabrication. To prevent the need for the syringe pumps and external piping networks, we have integrated the CIDS on a microfluidic disc to automate the whole bioanalytical process from sample preparation to characterization of thousands of particles and cells. The main objective of developing the integrated microfluidic platform is the separation of activated and non-activated leukocytes for automated early sepsis detection at point of care (POC). However, as an early proof of the practicality of CIDS-on-disc, in this study we employed the hybrid centrifugal microfluidic system for separating various sizes of polystyrene microbeads as well as different bacteria. [1] M.M. Aeinehvand, F. Ibrahim, S.W. Harun, A. Kazemzadeh, H.A. Rothan, R. Yusof, M. Madou, Reversible thermo-pneumatic valves on centrifugal microfluidic platforms, Lab Chip. 15 (2015) 3358–3369. doi:10.1039/C5LC00634A. [2] M.M. Aeinehvand, P. Magaña, M.S. Aeinehvand, O. Aguilar, M.J. Madou, S.O. Martinez-Chapa, Ultra-rapid and low-cost fabrication of centrifugal microfluidic platforms with active mechanical valves, RSC Adv. 7 (2017) 55400–55407. doi:10.1039/C7RA11532F. [3] J.L. Prieto, H.-W. Su, H.W. Hou, M.P. Vera, B.D. Levy, R.M. Baron, J. Han, J. Voldman, Monitoring sepsis using electrical cell profiling, Lab Chip. 16 (2016) 4333–4340. doi:10.1039/C6LC00940A.